Meaning
Liquid composite manufacturing involves the injection of a liquid polymer into a closed mold containing a dry fiber preform. The use of resin transfer molding allows for the production of complex shapes with high dimensional accuracy. This process is a staple of high-volume automotive and aerospace production.
Permeability Challenge
Fluid must travel through the tight gaps between fibers to ensure a complete fill. During resin transfer molding the injection pressure must be carefully balanced to prevent the fibers from shifting. If the resin moves too quickly it can trap air and create voids that weaken the part.
Cycle Economy
Efficiency is achieved by separating the fiber placement from the resin injection. In a resin transfer molding environment the mold can be used repeatedly with very little downtime. This makes the process more cost-effective than vacuum bagging for large production runs.
Surface Quality
Closed molds produce a smooth finish on all sides of the component. Parts made via resin transfer molding require less post-processing and sanding before they are painted. This reduction in labor costs is a primary driver for its adoption in the luxury vehicle market.
The success of the method depends on the precise timing of the resin chemistry to ensure the mold is full before the gelation begins.